Influence of Metalaxyl and CGA 62828 Adsorption on the Leaching Behavior of Metal‐Contaminated Soils

• Published in: Clean : soil, air, water Vol. 49; no. 5
• Main Authors: Bassil, Joseph, Azzi, Valérie, Naveau, Aude, Menhem, Tony, Rizk, Ibtihaj, El Samrani, Antoine G.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-05-2021
• Subjects: Adsorption; Biodegradation; CGA 62828; Drinking water; Environmental degradation; Environmental impact; Fungicides; Heavy metals; Industrial areas; Industrial pollution; Iron; Leaching; Metabolites; Metalaxyl; metallic elements; Pesticides; Saline soils; Sediment pollution; Soil; Soil contamination; Soil degradation; Soil pollution; Soil water; sorption; Zinc
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.202000277

Pesticides’ degradation in the environment affects their persistence and their environmental impact. In this study, batch experiments are performed to investigate 1) the adsorption of a fungicide, metalaxyl, and its main acid metabolite (CGA 62828) onto the surface of two different soils collected in the metal‐contaminated bay of an industrial area and 2) the influence of these two molecules on the leaching of soluble bases, iron and zinc, from the studied soils. In ultrapure water, adsorption isotherms show that the amount of CGA 62828 adsorbed by the soil particles are higher than the amount of metalaxyl. Furthermore, higher amount of these two molecules are adsorbed at a slower rate by the well‐drained soil in comparison with the more polluted saline anthroposol. In contrary to metalaxyl, CGA 62828 favors the release of the bases K, Na, and Ca by the saline soil in contact with ultrapure water. CGA 62828 also tends to limit the Fe and Zn release which are favored in the presence of metalaxyl. The composition of the local tap water did not significantly influence the adsorbed quantities of metalaxyl and CGA 62828 despite its impact on the Fe and Zn leaching.
The transformation of metalaxyl to CGA 62 828 affects its sorptive behavior in soils and influences the leaching of soluble bases and metallic elements. Batch experiments show that CGA 62 828 is more efficiently adsorbed at the surface of metal‐contaminated soils. The effect of the two molecules on the soil behavior in aqueous medium depends on the soil type.